Appliance for the ventilation of the crankcase of internal combustion engines



Jan. .28} 1958 A. SCHElTERLEIN 2 7 APPLIANCE FOR THE VENTILATION OF THECRANKCASE OF INTERNAL COMBUSTION ENGINES 2 Sheqts-Sheei 1 Filed May 27.1955 INVENTOR.

Jan. 28, 1958 A. SCHEITERLEIN APPLIANCE FOR THE VENTILATION OF THECRANKCASE OF INTERNAL COMBUSTION ENGINES Filed May 27. 1955 2Sheets-Sheet 2 INVENTOR.

United States Patent APPLIANCE FOR THE VENTILATION OF THE EIQRINNITIgASEOF INTERNAL COMBUSTION Andreas Scheiterlein, Graz, Austria, assignor toGustav Ospelt, Vaduz, Liechtenstein Application May 27, 1955, Serial No.511,719

Claims. (Cl. 121-194) This invention relates to an internal combustionengine, the crankcase of which is ventilated via a separate expandingand condensing chamber.

It is necessary and customary to ventilate the crankcase of four-strokeengines and two-stroke engines without a crankcase scavenging system bymaintaining a permanent connection between its interior and theatmosphere in order to avoid power and oil losses due to overpressurewhich might be produced by piston leakage. Yentilation is of particularimportance for two-stroke englnes with piston-controlled exhaust ports,if uncontrollable losses of lubricating oil between the pistons andcylinder walls and through the exhaust ports are to be avoided.

For the purpose of eliminating oil losses through the breather it isknown to provide an expanding and condensing chamber along the passageleading to the exhaust port inside the crankcase, permitting the oilcontained in the crankcase air in the vapor state to condense and flowback into the oil sump. The exhaust port is usually located at a highlevel of the crankcase and can be used simultaneously as an oil fillerinlet.

In these known designs the arrangement of a separate condensing chamberinvariably involves higher cost and the necessity of enlarging thecrankcase and consequently, the entire engine. This is particularly trueof engines with a lubricating system where oil is intentionally sprayedin the crankcase so as to feed it to certain points requiringlubrication, as a result of which the crankcase air contains a largeamount of oil. In order to eliminate these shortcomings the presentinvention provides for an expanding and condensing chamber formed by therear gear cover. As a result of this arrangement, the path of thecrankcase air to the exhaust port will be lengthened and the oilcondensation improved. At the same time, the design of the crankcase issimplified and its construction cost reduced and the overall dimensionsof the engine will be smaller.

The expanding and condensing chamber is preferably arranged in the reargear cover beside the chamber which houses the gears, both chambersbeing separated from each other at least partly by a partition. Thisaffords a very simple and space-saving shape of the cover and thejointly machined surface of attachment simultaneously provides theclosure of the smoothing chamber.

The invention is illustrated by way of example in the accompanyingdrawings wherein:

Figure 1 shows a vertical section through a twostroke engine, the coverpart being shown in section along the line I-I of Figure 2. Figure 2shows a rear view of the gear cover and Figure 3 a section of this coveralong the line IIIIII of Figure 2.

In Figure 1 only the flywheel end adjacent cylinder of the two-strokeengine with cylinders arranged in a row is shown. The crankcase isdesignated by 1, the cylinder liner by 2, the cylinder head by 3, thepiston by 4 and the connecting rod by 5. The end of the crankshaft 6carries the flywheel 7. Between the flywheel 7 and the last main bearing8 of the crankshaft, a gear wheel 9 is located on the crankshaft,driving the auxiliary machines not shown, such as the fuel injectionpump via the idler 10 and another gear wheel 11. The idler 10 can bedesigned as a counterbalancing wheel and is mounted on acounterbalaucing shaft 12 passing through the crankcase. The threeaforementioned gear wheels 9, 10 and 11 are in alignment and locatedoutside the crankcase 1 and covered by a gear cover 13.

The gear cover 13 is also part of the flywheel housing which is closedby a cover 14. It is secured by screws to the crankcase 1 with theinterposition of a plate 15. The bores 16 for the fixing screws areshown in Figure 2. The interior 17 of the gear cover serves to house thegear Wheels 9, 10 and 11. Separated from the chamber 17 by a partition18, an expanding and condensing chamber 19 is provided in the cover,with its lower portion communicating With the lower bottom half of thecrankcase and a vent 20 in its upper portion. The partition 18 is partlybent over the lower gear wheel 9 to prevent oil from being sprayed fromthe gear wheel 9 rotating in the direction of the arrow 21 directly intothe smoothing chamber. The expanding and condensing chamber 19 isupwardly enlarged so that the air flow from the crankcase to the vent 20will be slowed down still further. In addition, bafile plates 22, 23 ofa type known per se are arranged inside this chamber to divert the airand lengthen the flow path. These measures permit the separation of eventhe smallest drops of oil. The separated oil flows back to the oil sump24.

The partition 18 and the bafile plates 22 and 23 reach as far as theconnecting surface 25 of the gear cover 13 and are machined jointly withthe latter. They register with the fiat plate 15 located between thecrankcase 1 and the gear cover 13. This provides a lateral separation ofthe expanding and condensing chamber 19 from the chamber 17 of the gearwheels.

The vent 20 also serves as a filler inlet. For that purpose, a funneltube 26 is inserted in the vent and surrounded by the housing 27 whichcan be closed by means of a cover 28. If the cover 28 is closed, theventilation is effected through the funnel tube 26 and a tube 29 leadingdownward, of which the upper part only is shown in the drawing.

I claim:

1. In an internal combustion engine of the reciprocating piston typehaving a rotary crankshaft driven by the reciprocating piston, saidengine including a housing having a crankcase in which said crankshaftis rotatably disposed, said crankcase being open at one end, and thecorresponding end of the crankshaft projecting through said one end, agear fixed on said projecting end of the crankshaft, a gear coverclosing said open end of the crankcase and housing said gear, meanscooperating with said gear cover to define an oil condensing passageextending generally upwardly to one side of said gear from the lowerportion of said cover to a vent formed in the upper portion of saidcover, said passage being upwardly enlarged to lower the velocity of theair following its entry into said passage to permit an improvedseparation therefrom of oil particles and oil vapor for drainage intosaid crankcase.

2. The combination of claim 1 in which the said means cooperating withthe cover comprises a flat plate interposed between the upper portion ofsaid cover and the open end of the crankcase and terminating short ofthe lower extremity of said passage to establish communication thereofwith the crankcase.

3. The combination of claim 2 in which said cover is formed with arecess presented toward the crankcase for housing said gear, andprovided with an integral partition extending upwardly through saidrecess on one 5. The combination of claim 4 wherein said bafile side ofthe gear and in flush engagement with said flat plates extend into flushengagement with the said flat plate to define said passage. plate.

4. The combination of claim 3 including bafiie plates integral with thecover plate and projecting into said 5 References Clted the file of thisPatent passage from generally opposite sides thereof to direct UNITEDSTATES PATENTS the air through said passage in a tortuous path, thereby1,299,129 Coatalen APR 1, 1919 to prolong the retention of air in saidpassage and secure improved removal of oil particles and vapor from theair FOREIGN PATENTS within said'passage. 10 415,490 Germany June 25,1925

